Electric low-water alarm.



No. 703,472. Patented July I, 1902. E. w. moan. ELECTRIC LOW WATER ALARM.

(Applicafiion filed July 24, 1901.)

(No Model.)

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UNITED STATES PATENT Orrion.

EBENEZER IV. RIDER, OF DETROIT, MICHIGAN.

ELECTRIC LOW-WATER ALARM.

$PECIFICATION forming part of Letters Patent No. 703,472, dated July 1, 1902.

Application filed July 24,1901.

To all whom it may concern:

Be it known that I, EBENEZER \V. RIDER, a

citizen of the United States, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Electric Lowater Alarms; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of this specification.

My invention relates to electric low-water alarms for steam-boilers, and particularly to alarms operated by the expansion of a metallic tube connected to the boiler, the expansion being caused by steam entering the tube when the waterbecomes low. Existing alarms of this character are usually made of a single straight tube and have'the defect that a relatively long tube is required in order to secure the expansion necessary to close the electrical contact sounding the alarm. These alarms also have the defect that they communicate with the boiler at one end only, usually the lower end of a vertically-extending tube, whereby water is apt to and does become trapped in the tube, so that although the water in the boiler may fall below the mouth of the tube no steam enters the tube, and the device does not operate.

The object of my invention is to remedy these defects and to construct an alarm of superior simplicity which will be certain in operation.

A further object is to construct an alarm. of the character described which will be more sensitive than those heretofore constructed.

With these and other objects in view the invention is hereinafter described, and is illustrated in the accompanying drawings, in which-- Figure 1 is a side elevation of the invention as applied to a steam-boiler. Fig. 2 is a vertical longitudinal section thereof, showing parts in elevation.

Referring more particularly to the drawings, the alarm comprises a pipe 6, communicating with the boiler 6" above the normal water-line and fitted to the upper end of a tube.

projecting from the block 7.

Serial No. 69,495. (No model.)

block 7, from which the expansion-tube 8 projects at or about the low-water line. This expansion-tube is preferably U-shaped, and the upper arm thereof is provided at its end with threads and is screwed into the block 7, as indicated at 7. A passage 7 communicates between the pipe (3 and the expansion- The expansion-tube projects horizontally with respect to its length with its arms in a vertical plane. The lower arm 8 of the expansion -tube communicates with a passage 7, extending through the lower part of the block 7, and connects with the pipe 6, communicating with the boiler. pressure is thus provided, so that it is impossible for water to become trapped in the ex pansion-tube. It will be seen that as the water falls the steam enters through the pipe (5 and forces the Water to the same level as the water in the boiler.

The lower arm 8" is connected to the block by a packing-nut 9, which fits a screw-thread ed nipple 10 on the block. The arm 8 is movable longitudinally within the packingnut, a suitable steam-tight packing being interposed between them. By this construe-- tion expansion of the tube 8 takes place as soon as the steam enters the upper arm thereof, the lower arm 8 moving in the packingnut longitudinally to the slight extent neces-= sary to actuate the electric signal now to be described.

A bracket 11 is secured to the expansiontube at the bend thereof, and the bracket is provided with a set screw 12, extending through a screw-threaded perforation in the bracket. A jam-nut 13 serves to retain the set-screw at the desired adjustment. In order that the alarm may be very sensitive and respond quickly to the slightest expansion of the tube, the motion is multiplied by means of a compound lever consisting of a lever let, pivoted at 15 to an arm 16, secured to and The point of the screw 12 bears against this lever, the moving end of which is provided with a pin 11 in contact with the second lever 17, which is pivoted at one end 18 to the arm 19, also socured to and projecting from the block 7. The movable end of the second lever is provided with a pin 17 in contact with a spring-= strip 20, which is one of the electrical contact- A balanced pieces, the other electrical contact-piece being indicated at 21. These contact-pieces are supported upon the ends of the arms 16 and 19, insulated therefrom by pieces 22 of any suitable insulating material. A bar of insulating material 23 connects the ends of the arms. The contact-pieces are connected to wires 24-, which communicate with an electric bell of any ordinary construction. I have considered it unnecessary to illustrate the bell, as the manner of operation will be readilyunderstood. The conuectionbetween the wires and the contact-pieces may be made in auysuitable manner. I have shown binding-nuts 25 extending through the insulating-bar 23. into contact with the contactpieces.

In the drawings I have shown the alarm as connected directly and independently to the boiler. It will be understood that it may be connected to the water-column or to the water-gage. In fact, the latter is a preferable construction for the sake of convenience, the glass of the water-gage being connected to the top of the block instead of the pipe (3.

It will be seen that by the construction described the alarm occupies very little space; also that Water cannot become trapped in the expansion-tube and the device thus made uncertain of operation, as in existing tubes having only one connection with the boiler; also that a very sensitive alarm is formed. Very slight movement of the expansion-tube is communicated through and compounded by the levers and the spring 20 thrown into contact with the contact-piece 21, whereby the circuit is closed and the bell sounded. The set-screw 12 permits a very delicate adjust-- ment of the distance between the contactpieces.

Having thus described the invention, what I claim as new, and desire to secure by Letters Patent, is-

roe r22 1. In an electric low-water alarm, in combination, an expansible tube through which the boiler contents can flow having a plurality of connections with the boiler at different levels thereof, and means operated by the expansion of the tube to actuate an electric signal.

2. In an electric low-water alarm, in combination, a horizontal U-shaped expansible tube, each arm of which communicates with the boiler at a different level, and means operated by the expansion of the tube to actuate an electric signal.

In an electric low-water alarm, in combination, a bent expansible tube, the upper end of which communicates with an upper level of the boiler, a pipe communicating with the lower end of the tube from a lower level of the boiler, an expansion-joint between the pipe and said lower end, a lever connected to the tube, a contact device operated by the lever and adapted to close an electric circuit, and a signal device in said circuit.

at. In an electric low-Water alarm, in combination, a pipe communicating with the boiler at an upper level, a U-shaped expansible tube, a connection between the said pipe and the upper arm of the tube, a lower pipe communicating with the boiler at a lower level, an expansion-joint between the lower pipe and the lower arm of the tube, a compound lever, an adjustable connection between the lever and the tube, contact-pieces adapted to be actuated by the lever to close an electric circuit, and a signal device in the circuit.

In testimony whereof I al'fix my signature in presence of two witnesses.

EBENEZER IV. RIDER.

Witnesses:

HENRY Llvr'uLIr, FRANK M. S'JEWAR'I. 

